<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style>
	.clearfix:after {  /*正常浏览器 清除浮动*/
		content:"";
		display: block;
		height: 0;
		clear: both;
		visibility: hidden;
	}
	.clearfix {
		*zoom: 1;  /*zoom 1 就是ie6 清除浮动方式  *  ie7一下的版本所识别*/
	}
	.father {
		border: 1px solid red;
		width: 300px;

	}
	.big {
		width: 100px;
		height: 100px;
		background-color: purple;
		float: left;
	}
	.small {
		width: 80px;
		height: 80px;
		background-color: blue;
		float: left;
	}
	.footer {
		width: 400px;
		height: 100px;
		background-color: pink;
	}
	</style>
</head>
<body>
	<div class="father clearfix">
		<div class="big"></div>
		<div class="small"></div>
	</div>
	<div class="footer"></div>
</body>
</html>